code: def compute_projection(self):
      modelview = GL.glGetDoublev(GL.GL_MODELVIEW_MATRIX)
      projection = GL.glGetDoublev(GL.GL_PROJECTION_MATRIX)
      mvp = projection.T @ modelview.T
      mvp = QtGui.QMatrix4x4(mvp.ravel().tolist())
  
      # note that QRectF.bottom() != QRect.bottom()
      rect = QtCore.QRectF(self.view().rect())
      ndc_to_viewport = QtGui.QMatrix4x4()
      ndc_to_viewport.viewport(
          rect.left(), rect.bottom(), rect.width(), -rect.height()
      )
  
      return ndc_to_viewport * mvp
  
file_path: pyqtgraph/pyqtgraph/examples/GLPainterItem.py
imports: import OpenGL.GL
  import pyqtgraph
  from pyqtgraph.opengl import GLAxisItem, GLGraphicsItem, GLGridItem, GLViewWidget
  from pyqtgraph.Qt import QtCore, QtGui
label_desc: Use image node_id 2 for calling the GLPainterItem obj's underlying member method code with example usage: obj.compute_projection() and returns: unknown